A View from the Moon: Kepler's Somnium as a Thought Experiment in Astronomy

Abstract

In 1634, Somnium – ‘A Dream’ – written by the famous astronomer Johannes Kepler [1571- 1630], was published posthumously. Somnium is a work of fiction in which a journey to the Moon is described. This thesis argues that Somnium should be read as a thought experiment that was intended to convince readers of Copernicus’ theory of the Earth’s diurnal rotation around its axis. For this purpose, Kepler devised an imaginary scenario that would provide ‘visual evidence’ of the rotation of the Earth. The planetary movement described in Somnium is not the result of an unconstrained imagination. Quite to the contrary, this thesis argues that Somnium offers a rigorous and scientifically-based imaginary scenario meant to prompt its readers to entertain new scientific possibilities.